scsi: qla2xxx: Delay module unload while fabric scan in progress

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Delay module unload while fabric scan in progress System crash seen during load/unload test in a loop. [105954.384919] RBP: ffff914589838dc0 R08: 0000000000000000 R09: 0000000000000086 [105954.384920] R10: 000000000000000f R11: ffffa31240904be5 R12: ffff914605f868e0 [105954.384921] R13: ffff914605f86910 R14: 0000000000008010 R15: 00000000ddb7c000 [105954.384923] FS: 0000000000000000(0000) GS:ffff9163fec40000(0000) knlGS:0000000000000000 [105954.384925] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [105954.384926] CR2: 000055d31ce1d6a0 CR3: 0000000119f5e001 CR4: 0000000000770ee0 [105954.384928] PKRU: 55555554 [105954.384929] Call Trace: [105954.384931] <IRQ> [105954.384934] qla24xx_sp_unmap+0x1f3/0x2a0 [qla2xxx] [105954.384962] ? qla_async_scan_sp_done+0x114/0x1f0 [qla2xxx] [105954.384980] ? qla24xx_els_ct_entry+0x4de/0x760 [qla2xxx] [105954.384999] ? __wake_up_common+0x80/0x190 [105954.385004] ? qla24xx_process_response_queue+0xc2/0xaa0 [qla2xxx] [105954.385023] ? qla24xx_msix_rsp_q+0x44/0xb0 [qla2xxx] [105954.385040] ? __handle_irq_event_percpu+0x3d/0x190 [105954.385044] ? handle_irq_event+0x58/0xb0 [105954.385046] ? handle_edge_irq+0x93/0x240 [105954.385050] ? __common_interrupt+0x41/0xa0 [105954.385055] ? common_interrupt+0x3e/0xa0 [105954.385060] ? asm_common_interrupt+0x22/0x40 The root cause of this was that there was a free (dma_free_attrs) in the interrupt context. There was a device discovery/fabric scan in progress. A module unload was issued which set the UNLOADING flag. As part of the discovery, after receiving an interrupt a work queue was scheduled (which involved a work to be queued). Since the UNLOADING flag is set, the work item was not allocated and the mapped memory had to be freed. The free occurred in interrupt context leading to system crash. Delay the driver unload until the fabric scan is complete to avoid the crash.